Electrical connector

CROSS-REFERENCE TO RELATED APPLICATIONS

0001This application is a national phase of International Application No. PCT/JP04/018688, filed Dec. 8, 2004, which claims priority from Japanese Patent Application No. 2004-1,524, filed Jan. 7, 2004, each of which are incorporated by reference in their entireties herein, and from which priority is claimed.

TECHNICAL FIELD

0002This invention relates to a plug connector for use with appliances such as a mobile phone or cellular telephone, notebook personal computer, digital camera and the like, and more particularly to a construction for achieving the flat geometry of a plug connector.

0003There is no particularly relevant patent literature disclosed within scope of our research. In order to reduce the noise in appliances, coaxial cables <b>14</b> have frequently been used because of their shielding effects. For example, as shown in <figref idref="DRAWINGS">FIGS. 8 and 9</figref>, for the purpose of connecting the coaxial cables <b>14</b> to a hard substrate, a plug connector <b>60</b> and a receptacle connector <b>80</b> have been used. Namely, the coaxial cables <b>14</b> are connected to the plug connector <b>60</b>, while the hard substrate is connected to the receptacle connector <b>80</b>. The plug connector <b>60</b> and the receptacle connector <b>80</b> are then fitted with each other so that the coaxial cables <b>14</b> are brought into connection with the hard substrate, thereby accomplish the continuity therebetween.

0004An example of electrical connectors of prior art will be explained with reference to <figref idref="DRAWINGS">FIGS. 8 and 9</figref>. The electrical connector <b>5</b> comprises a plug connector <b>60</b> and a receptacle connector <b>80</b> detachably fitted with each other. <figref idref="DRAWINGS">FIG. 8</figref> illustrates in a perspective view the plug and receptacle connectors <b>60</b> and <b>80</b> prior to being fitted with each other. <figref idref="DRAWINGS">FIG. 9</figref> shows in a perspective view the plug connector <b>60</b> with the plug shell removed.

0005The plug connector <b>60</b> mainly comprises a block <b>62</b>, plug contacts <b>64</b>, a ground bar <b>66</b>, and a plug shell <b>68</b>. The receptacle connector <b>80</b> mainly comprises a housing <b>82</b>, contacts, and a receptacle shell <b>88</b>.

0006First, the block <b>62</b> of the plug connector <b>60</b> includes an inserting hole <b>70</b> into which coaxial cables <b>14</b> are inserted as shown in <figref idref="DRAWINGS">FIG. 8</figref>. After the coaxial cables <b>14</b> are inserted into the inserting hole <b>70</b>, center conductors <b>141</b> of the coaxial cables <b>14</b> are each connected to the plug contact <b>64</b>, and the braids <b>143</b> of the coaxial cables <b>14</b> are connected to the ground bar <b>66</b> as by soldering or insulation displacement. Thereafter, the plug shell <b>68</b> thus combined with the other members is fitted on the block <b>62</b>. The block <b>62</b> is provided with a plurality of protrusions <b>76</b> like teeth of a comb for arranging the coaxial cables <b>14</b> as shown in <figref idref="DRAWINGS">FIG. 9</figref>. The center conductors <b>141</b> of the coaxial cables <b>14</b> are each connected to the connection portion of the plug contact <b>64</b> in one of loading portions <b>74</b> in the block <b>62</b>. The plug shell <b>68</b> is provided with a plurality of anchoring pieces <b>78</b> and a plurality of contact pieces <b>79</b>. The anchoring pieces <b>78</b> contact the grand bar <b>66</b> to cause the continuity of the coaxial cables <b>14</b> and the plug shell <b>68</b>, thereby providing grounding. Consequently, when the plug connector <b>60</b> and the receptacle connector <b>80</b> are fitted with each other, the contact pieces <b>79</b> of the plug shell <b>68</b> contact the receptacle shell <b>88</b> which has been fixed to a hard substrate to cause the continuity of the coaxial cables <b>14</b> and the hard substrate, thereby achieving the overall grounding. On the opposite side of the inserting hole <b>70</b>, moreover, there is provided a fitting portion <b>72</b> for fitting with or connecting to the receptacle connector <b>80</b>. At the fitting portion <b>72</b>, the plug contacts <b>64</b> are arranged and held so that these plug contacts <b>64</b> are brought into contact with the contacts <b>82</b> of the receptacle connector <b>80</b> when the plug and receptacle connectors are fitted with each other. The plug contacts <b>64</b> each mainly comprise a contact portion <b>641</b> adapted to contact the receptacle connector <b>80</b>, a fixed portion held by the block <b>62</b>, and a connection portion <b>643</b> to be connected to the coaxial cable <b>14</b>.

0007On the other hand, the receptacle connector <b>80</b> includes a fitting opening <b>52</b> into which the plug connector <b>60</b> is inserted as shown in <figref idref="DRAWINGS">FIG. 8</figref>. Contact portions of the contacts are arranged and held in the fitting opening <b>52</b> so as to extend into the fitting opening so that the continuity of the plug and receptacle connectors <b>60</b> and <b>80</b> can be achieved by inserting the fitting portion <b>72</b> of the plug connector <b>60</b> into the fitting opening <b>52</b>. The contacts each mainly comprise a contact portion adapted to contact the contact portion of the plug contact <b>64</b>, a fixed portion held by the housing <b>82</b>, and a connection portion to be connected to a hard substrate. The receptacle shell <b>88</b> is installed in the housing <b>82</b> by press-fitting, lancing or hooking. The receptacle shell <b>88</b> is provided with fixing tabs <b>54</b> which are soldered to the hard substrate as by reflow soldering together with the connection portions of the contacts.

0008In recent years, with miniaturization of electronic or electrical appliances such as a mobile phone, the requirement for more miniaturization, particularly flat geometry or vertical size for reducing the thickness has put more severe pressure on receptacle connectors to be mounted with the above-mentioned appliances and plug connectors to be fitted with the receptacle connectors.

0009With the construction of the plug connector described above, however, the thicknesses of the plug contacts and the thickness of the block required for holding the plug contacts have minimum limitations which make it impossible to realize a flat geometry less than 1.4 mm of the plug connector as a problem to be solved.

0010On the other hand, even with the construction of the receptacle connector described above, it requires to some extent to have thicknesses of side walls of the housing at the both ends, the contact portions of the contacts arranged on both the sides, and fitting portion of the plug connector to be inserted in the fitting opening, and particularly the thickness of the fitting portion of the plug connector is approximately one third of the overall thickness. Therefore, the flat geometry of the plug connector is unavoidable in order to achieve the flat geometry of the receptacle connector.

0011With the construction of the plug connector, moreover, in the case that coaxial cables having a fine diameter are used with a narrow pitch, when the braids of the coaxial cables are connected to the ground bar by soldering, the insulators of the coaxial cables tend to melt by the heat of the soldering to cause the continuity of the braids and the center conductors, resulting into failed connection.

0012With the construction of the plug connector described above, as the coaxial cables are connected to a rigid body not having a flexibility, the connection portions of the coaxial cables tend to be partly broken depending on the used condition such as being bent, resulting into defective connection. Moreover, requirements for more shielding have progressively increased with the use of high-speed transmission of electronic appliances.

0013Furthermore, there is a requirement to prevent an erroneous fitting to insert the plug connector upside down into the receptacle connector in view of problems of misconnection and to prevent a problem of destruction of the plug connector or the receptacle connector.

SUMMARY OF THE INVENTION

0014It is an object of the invention to provide an improved electrical connector which eliminate all the disadvantages of the prior art, and which achieves the flat geometry of its plug connector <b>60</b> and hence of its receptacle connector <b>80</b> to the desired extent and can preclude any defective connection between a ground bar <b>66</b> and coaxial cables <b>14</b>.

0015The object described above can be achieved by an electrical connector <b>1</b> including a plug connector <b>10</b> and a receptacle connector <b>40</b> detachably fitted with each other, wherein according to the invention the plug connector <b>10</b> comprises a plurality of coaxial cables <b>14</b> each having a center conductor <b>141</b>, an insulator <b>142</b> covering the center conductor <b>141</b>, a braid <b>143</b> as an external conductor covering the insulator <b>142</b>, and a sheath <b>144</b> covering the braid <b>143</b>; a flexible printed circuit board <b>12</b> having lands <b>28</b> each connected to the center conductor <b>141</b> of the coaxial cable <b>14</b> and land portions <b>30</b> to which a ground bar <b>16</b> is connected; and the ground bar <b>16</b> having a main portion <b>22</b> adapted to contact the braids <b>143</b> and fixed portions <b>24</b> each positioned contiguously with the main portion <b>22</b> and connected to the land portion <b>30</b>.

0016In a preferred embodiment of the invention, the receptacle connector <b>40</b> comprises a housing <b>42</b>, contacts <b>44</b>, locking lever <b>46</b>, and a receptacle shell <b>48</b> covering the housing <b>42</b> except for its portion associated with the locking lever <b>46</b>, and the receptacle shell <b>48</b> is provided on the side of a fitting opening <b>52</b> with at least one contacting means adapted to contact the upper surface of the ground bar <b>16</b> of the plug connector <b>10</b>. In this manner, the receptacle shell <b>48</b> and the ground bar <b>16</b> are securely brought into contact with each other, thereby more easily and more certainly achieving the continuity between the coaxial cables <b>14</b> and a hard substrate and providing grounding.

0017Preferably, the ground bar <b>16</b> of the plug connector <b>10</b> is provided with projection pieces <b>26</b> which extend from the main portion <b>22</b> of the ground bar <b>16</b> and is adapted to contact the braids <b>143</b> at locations between the center conductors of all the coaxial cables or at locations between the center conductors of every other coaxial cable <b>14</b>. Moreover, the ground bar <b>16</b> of the plug connector <b>10</b> is provided with projection pieces <b>26</b> which extend from the main portion <b>22</b> of the ground bar and is adapted to contact the braids <b>143</b> at intervals of plural locations between the coaxial cables <b>14</b>. The projection pieces <b>26</b> are brought into contact with the braids <b>143</b> of the coaxial cables <b>14</b> in this manner to eliminate soldering therebetween, thereby precluding any defective connection caused by melting of the insulator <b>142</b> by heat in soldering.

0018In a preferred embodiment, the projection pieces <b>26</b> are in the form of a substantially L-shape. By forming the projection pieces in the form of the substantially L-shape, the ground bar <b>16</b> is only put on the coaxial cables to cause the projection pieces <b>26</b> in the form of comb teeth to insert into between the braids <b>143</b> of the coaxial cables <b>14</b>. In the case that the pitch of the coaxial cables <b>14</b> is narrow such as 0.3 mm, the projection pieces <b>26</b> may be a substantially L-shape whose leading end may be of a substantially sharp triangle so that the triangular portions are simply caused to contact between the braids <b>143</b> of the coaxial cables without insertion of the triangular portions, thereby achieving the above effect.

0019Preferably, the projection pieces <b>26</b> in the form of the substantially L-shape located at intervals of plural locations extend beyond the braids <b>143</b> and fixed to the flexible printed circuit board <b>12</b> by soldering. In this manner, the ground bar <b>16</b> is prevented from rising away from the coaxial cables.

0020The contacts <b>44</b> at both the ends of the receptacle connector <b>40</b> are preferably each connected to the land portion <b>30</b>. With this construction, the continuity between the coaxial cables <b>14</b> and the hard substrate can be readily achieved, thereby providing the grounding.

0021One preferred embodiment according to the invention, each of the contacts <b>44</b> of the receptacle connector <b>40</b> comprises a contact portion <b>441</b>, a connection portion <b>443</b>, an elastic portion <b>445</b> and a fulcrum portion <b>444</b> provided between the contact portion <b>441</b> and the connection portion <b>443</b>, a pressure receiving portion <b>446</b> positioned opposed to the connection portion <b>443</b> and extending from the elastic portion <b>445</b>, and an extension portion having a further contact portion <b>441</b> on the opposite side of the first mentioned contact portion <b>441</b>, and the first mentioned contact portion <b>441</b>, the elastic portion <b>445</b>, the fulcrum portion <b>444</b> and the connection portion <b>443</b> are arranged in the form of a crank, and further the locking lever <b>46</b> of the receptacle connector <b>40</b> is provided with urging portions <b>461</b> successively in its longitudinal direction, and the locking lever <b>46</b> is installed in the housing <b>42</b> so that the urging portions <b>461</b> are each pivotally movable in the space between the connection portion <b>443</b> and the pressure receiving portion <b>446</b> of the contact <b>44</b>. By using the receptacle connector <b>40</b> having such a construction, the electrical connector will become of “ZIP (zero-insertion force)” type so that the plug connector <b>10</b> can be easily fitted in the receptacle connector <b>40</b>, resulting in enhancing of the flat geometry of the receptacle connector <b>40</b>.

0022More preferably, the receptacle connector <b>40</b> is provided with locking members <b>50</b> in the same construction as that of the contacts <b>44</b>, and the flexible printed circuit board <b>12</b> is provided with anchoring portions <b>32</b> each at position corresponding to engaging portion <b>501</b> of the locking member <b>50</b>. By providing the locking members <b>50</b> in this manner, a stable holding force can be obtained when the plug and receptacle connectors <b>10</b>, <b>40</b> are fitted with each other.

0023In one preferable embodiment of the invention, as the contact means of the receptacle shell <b>48</b> there is provided a protrusion <b>56</b> extending into the fitting opening <b>52</b> or an elastic piece <b>57</b> having an elasticity extending into the fitting opening <b>52</b>. By providing such contact means, the receptacle shell <b>48</b> and the ground bar <b>16</b> can be more securely caused to contact with each other, and the continuity therebetween can be easily achieved.

0024Explaining the function of the receptacle connector <b>40</b> further, the plug connector <b>10</b> is inserted with its flexible printed circuit board and the coaxial cables into the fitting opening <b>52</b> of the housing <b>42</b> of the receptacle connector <b>40</b>, and then the locking lever <b>46</b> is pivotally moved in the direction shown by an arrow A in <figref idref="DRAWINGS">FIG. 2</figref>. As a result, the pressure receiving portions <b>446</b> of the contacts <b>44</b> are raised with the aid of the variation in contact height owing to, for example, the elliptical shape of the urging portions <b>461</b> so that the elastic portions <b>445</b> of the contacts <b>44</b> are tilted about their fulcrum portions <b>444</b> toward the contact portions <b>441</b> to urge the contact portions <b>441</b> toward the flexible printed circuit board <b>12</b>, thereby bringing the contact portions <b>441</b> into contact with the flexible printed circuit board <b>12</b>.

0025The ground bar <b>16</b> is provided with protrusion pieces <b>27</b> contiguously with the main portion <b>22</b> at predetermined positions on the surface of the main portion <b>22</b> of the ground bar <b>16</b>. The protrusion pieces <b>27</b> are caused to pierce into the coaxial cables <b>14</b> so that the ground bar <b>16</b> is brought into contact with the center conductors <b>141</b> and the braids <b>143</b> of the coaxial cables <b>14</b>, thereby obtaining the grounding between the coaxial cables <b>14</b> to achieve the shielding effect.

0026The protrusion pieces <b>27</b> of the grand bar <b>16</b> are arranged so that the protrusion pieces <b>27</b> will pierce into every other or every third coaxial cable. In this manner, the grounding can be obtained between the every other coaxial cable <b>14</b> or every third coaxial cable <b>14</b> to achieve the shielding effect.

0027As can been seen from the above explanation, the plug connector <b>10</b> according to the invention can bring about the following significant effects. <ul id="ul0001" list-style="none"><li id="ul0001-0001" num="0028">(1) In an electrical connector <b>1</b> including a plug connector <b>10</b> and a receptacle connector <b>40</b> detachably fitted with each other, according to the invention the plug connector <b>10</b> comprises a plurality of coaxial cables <b>14</b> each having a center conductor <b>141</b>, an insulator <b>142</b> covering the center conductor <b>141</b>, a braid <b>143</b> as an external conductor covering the insulator <b>142</b>, and a sheath <b>144</b> covering the braid <b>143</b>; a flexible printed circuit board <b>12</b> having lands <b>28</b> each connected to the center conductor <b>141</b> of the coaxial cable <b>14</b> and land portions <b>30</b> to which a ground bar <b>16</b> is connected; and the ground bar <b>16</b> having a main portion <b>22</b> adapted to contact the braids <b>143</b> and fixed portions <b>24</b> each positioned contiguously with the main portion <b>22</b> and connected to the land portion <b>30</b>. With such a construction, it is possible to make the plug connector <b>10</b> to be of an extremely flat geometry such as a height less than 0.6 mm and hence the receptacle connector <b>40</b> to be of a flat geometry of the order of 1.0 mm. Moreover, the grand bar <b>16</b> and the coaxial cables <b>14</b> are in a merely contacting relationship to one another, so that any melting of the insulators <b>142</b> is precluded and hence any defective connection is eliminated.</li><li id="ul0001-0002" num="0029">(2) According to the invention, the receptacle connector <b>40</b> comprises a housing <b>42</b>, contacts <b>44</b>, locking lever <b>46</b>, and a receptacle shell <b>48</b> covering the housing <b>42</b> except for its portion associated with the locking lever <b>46</b>, and the receptacle shell <b>48</b> is provided on the side of a fitting opening <b>52</b> with at least one contacting means adapted to contact the upper surface of the ground bar <b>16</b> of the plug connector <b>10</b>. Therefore, the ground bar <b>16</b> can be securely brought into contact with the receptacle shell <b>48</b> so that the coaxial cables <b>14</b> and a hard substrate can be easily brought into continuity relation, thereby providing the grounding.</li><li id="ul0001-0003" num="0030">(3) According to the invention, the ground bar <b>16</b> of the plug connector <b>10</b> is provided with projection pieces <b>26</b> which extend from the main portion <b>22</b> of the ground bar <b>16</b> and is adapted to contact the braids <b>143</b> at locations between the center conductors of all the coaxial cables <b>14</b> or at locations between the center conductors of every other coaxial cable <b>14</b>. Therefore, the grounding of the ground bar <b>16</b> and the braids <b>143</b> can be easily achieved. Moreover, there is no need for soldering the projection pieces <b>26</b> and the braids <b>143</b>, so that the risk of melting of the insulators <b>142</b> is eliminated, thereby completely preventing any failed connection.</li><li id="ul0001-0004" num="0031">(4) According to the invention, the ground bar <b>16</b> of the plug connector <b>10</b> is provided with projection pieces <b>26</b> which extend from the main portion <b>22</b> of the ground bar <b>16</b> and is adapted to contact the braids <b>143</b> at intervals of plural locations between the coaxial cables <b>14</b>. In the same manner as described above, the grounding of the ground bar <b>16</b> and the braids <b>143</b> can be easily achieved, and there is no need for soldering the projection pieces <b>26</b> and the braids <b>143</b>, so that the risk of melting of the insulators <b>142</b> is eliminated, thereby completely preventing any failed connection.</li><li id="ul0001-0005" num="0032">(5) According to the invention, the projection pieces <b>26</b> are in the form of a substantially L-shape. As a result, on putting the ground bar <b>16</b> onto the coaxial cables only, the projection pieces <b>26</b> in the form of comb teeth are inserted between the braids <b>143</b> of the coaxial cables <b>14</b>, thereby easily providing the grounding of the ground bar <b>16</b> and the coaxial cables <b>14</b>.</li><li id="ul0001-0006" num="0033">(6) According to the invention, the projection pieces <b>26</b> in the form of the substantially L-shape located at intervals of plural locations extend beyond the braids <b>143</b> and fixed to the flexible printed circuit board <b>12</b> by soldering. With this construction, the ground bar <b>16</b> is prevented from rising away from the coaxial cables <b>14</b>, thereby ensuring stable grounding.</li><li id="ul0001-0007" num="0034">(7) According to the invention, the contacts <b>44</b> at both the ends of the receptacle connector <b>40</b> are each connected to the land portion <b>30</b>. Accordingly, the continuity can be obtained between the ground bar <b>16</b> and the coaxial cables <b>14</b> or between the ground bar <b>16</b> and the hard substrate and hence the continuity can be easily realized between the coaxial cables <b>14</b> and the hard substrate, and the grounding of the coaxial cables <b>14</b> and the hard substrate is also possible.</li><li id="ul0001-0008" num="0035">(8) According to the invention, each of the contacts <b>44</b> of the receptacle connector <b>40</b> comprises a contact portion <b>441</b>, a connection portion <b>443</b>, an elastic portion <b>445</b> and a fulcrum portion <b>444</b> provided between the contact portion <b>441</b> and the connection portion <b>40</b>, a pressure receiving portion <b>446</b> positioned opposed to the connection portion <b>443</b> and extending from the elastic portion <b>445</b>, and a further contact portion <b>441</b> on the opposite side of the first mentioned contact portion <b>441</b>, and the first mentioned contact portion <b>441</b>, the elastic portion <b>445</b>, the fulcrum portion <b>444</b> and the connection portion <b>443</b> are arranged in the form of a crank, and further the locking lever <b>46</b> of the receptacle connector <b>40</b> is provided with urging portions <b>461</b> successively in its longitudinal direction, and the locking lever <b>46</b> is installed in the housing <b>42</b> so that the urging portions <b>461</b> are each pivotally movable in the space between the connection portion <b>443</b> and the pressure receiving portion <b>446</b> of the contact <b>44</b>. Accordingly, the receptacle connector <b>40</b> becomes of ZIF type (zero insertion force type) so that the plug connector <b>10</b> can be readily fitted in the receptacle connector <b>40</b>, and the flat geometry of the receptacle connector <b>40</b> is also achieved.</li><li id="ul0001-0009" num="0036">(9) According to the invention, the receptacle connector <b>40</b> is provided with locking members <b>50</b> in the same construction as that of the contacts <b>44</b>, and the flexible printed circuit board <b>12</b> is provided with anchoring portions <b>32</b> each at position corresponding to engaging portion <b>501</b> of the locking member <b>50</b>. With this construction, even if the number of the coaxial cables <b>14</b> is fewer, the stable holding force can be obtained when the plug and receptacle connectors <b>10</b>, <b>40</b> are fitted with each other.</li><li id="ul0001-0010" num="0037">(10) According to the invention, as the contact means of the receptacle shell <b>48</b> there is provided a protrusion <b>56</b> extending into the fitting opening <b>52</b> or an elastic piece <b>57</b> having an elasticity extending into the fitting opening <b>52</b>. Accordingly, the grand bar <b>16</b> can be more securely brought into contact with the receptacle shell <b>48</b> and the continuity therebetween can be easily achieved.</li><li id="ul0001-0011" num="0038">(11) According to the invention, the ground bar is provided with protrusion pieces <b>27</b> contiguously with the main portion <b>22</b> of the ground bar <b>16</b> at predetermined positions on the surface to contact the coaxial cables <b>14</b> so that the protrusion pieces are each adapted to pierce into the coaxial cable <b>14</b>, thereby causing each the protrusion piece <b>27</b> to contact the center conductor <b>141</b> and the braid <b>143</b> of the coaxial cable <b>14</b>. With such a construction, the shielding effect can be obtained between the predetermined coaxial cables <b>14</b> and also between the predetermined lands <b>28</b> of the flexible printed circuit board <b>12</b>.</li><li id="ul0001-0012" num="0039">(12) According to the invention, the protrusion pieces of the ground bar are so arranged that they pierce every other or every third coaxial cable. Therefore, the grounding and hence the shielding effect are also obtained even between the every other coaxial cable <b>14</b> or between the every third coaxial cable <b>14</b>. Further, the grounding and hence the shielding effect are also obtained even between the predetermined lands <b>28</b> of the flexible printed circuit board <b>12</b>.</li><li id="ul0001-0013" num="0040">(13) According to the invention, the protrusions extending from the fixed portions of the ground bar abut against the flat portion of the housing of the receptacle connector, when the plug connector erroneously turned upside down is being inserted into the receptacle connector. Therefore, the erroneous insertion of the plug connected into the receptacle connector can be prevented with the simple construction before the contacts of both the connectors contact each other even with a flexible printed circuit board having contact portions on its opposite sides. Accordingly, the erroneous insertion of plug connector upside down can be prevented with great certainty, thereby completely avoiding any failed connection.</li><li id="ul0001-0014" num="0041">(14) According to the invention, the protrusions are substantially L-shaped to ensure that the L-shaped portions abut against the flat portions of the housing. Therefore, the erroneous insertion of the plug connector turned upside down can be readily prevented.</li><li id="ul0001-0015" num="0042">(15) According to the invention, there are provided the required number of locking members depending upon required holding forces for plug and receptacle connectors. Accordingly, the holding forces can be assured according to specifications or customers demands.</li></ul>

BRIEF DESCRIPTION OF THE DRAWINGS

0043<figref idref="DRAWINGS">FIG. 1</figref> is a perspective view of a plug connector and a receptacle connector fitted with each other according to the invention;

0044<figref idref="DRAWINGS">FIG. 2</figref> is a perspective view of the plug connector and the receptacle connector before being fitted with each other according to the invention;

0045<figref idref="DRAWINGS">FIG. 3</figref> is a perspective view of the plug connector shown in <figref idref="DRAWINGS">FIG. 2</figref>, being turned upside down;

0046<figref idref="DRAWINGS">FIG. 4A</figref> is a perspective view of the plug connector and contacts and locking members of the receptacle connector according to the invention;

0047<figref idref="DRAWINGS">FIG. 4B</figref> is a perspective view illustrating the state of the contacts and locking members in contact with the plug connector shown in <figref idref="DRAWINGS">FIG. 4A</figref>;

0048<figref idref="DRAWINGS">FIG. 5</figref> is a perspective view of a locking lever as a single entity of the receptacle connector according to the invention.

0049<figref idref="DRAWINGS">FIG. 6A</figref> is a perspective view of a receptacle connector and a plug connector fitted with each other according to another embodiment of the invention;

0050<figref idref="DRAWINGS">FIG. 6B</figref> is a perspective view of a receptacle connector and a plug connector fitted with each other according to a further embodiment of the invention;

0051<figref idref="DRAWINGS">FIG. 7A</figref> is a perspective view illustrating a ground bar having protrusion pieces of the ground bar piercing into coaxial cables;

0052<figref idref="DRAWINGS">FIG. 7B</figref> is a perspective view illustrating the coaxial cables into which the protrusion pieces pierce and whose center conductors are soldered to lands of a flexible printed circuit board;

0053<figref idref="DRAWINGS">FIG. 8</figref> is a perspective view of a plug connector and a receptacle connector of the prior art before being fitted with each other;

0054<figref idref="DRAWINGS">FIG. 9</figref> is a perspective view of the plug connector of the prior art with the plug shell removed.

0055<figref idref="DRAWINGS">FIG. 10</figref> is a perspective view illustrating the plug and receptacle connectors having erroneous insertion preventing means according to the invention immediately before the correct insertion;

0056<figref idref="DRAWINGS">FIG. 11</figref> is a perspective view illustrating the plug and receptacle connectors correctly fitted with each other;

0057<figref idref="DRAWINGS">FIG. 12</figref> is a perspective view of the erroneously inserted plug connector into the receptacle connector being prevented its further insertion from the shown position by means of the erroneous insertion preventing means according to the invention; and

0058<figref idref="DRAWINGS">FIG. 13</figref> is a perspective view of the plug and receptacle connectors shown in <figref idref="DRAWINGS">FIG. 12</figref> viewed from the opposite side to illustrate the protrusions of the ground bar and the flat portions of the housing of the receptacle connector, which form the erroneous insertion preventing means according to the invention.

DESCRIPTION OF THE REFERENCE NUMERALS

0000<ul id="ul0002" list-style="none"><li id="ul0002-0001" num="0059"><b>1</b>, <b>5</b> Electrical connector</li><li id="ul0002-0002" num="0060"><b>10</b>, <b>60</b> Plug connector</li><li id="ul0002-0003" num="0061"><b>12</b> Flexible printed circuit board</li><li id="ul0002-0004" num="0062"><b>14</b> Coaxial cable</li><li id="ul0002-0005" num="0063"><b>141</b> Center conductor</li><li id="ul0002-0006" num="0064"><b>142</b> Insulator</li><li id="ul0002-0007" num="0065"><b>143</b> braid</li><li id="ul0002-0008" num="0066"><b>144</b> Sheath</li><li id="ul0002-0009" num="0067"><b>16</b>, <b>66</b> Ground bar</li><li id="ul0002-0010" num="0068"><b>22</b> Main portion</li><li id="ul0002-0011" num="0069"><b>24</b> Fixed portion</li><li id="ul0002-0012" num="0070"><b>26</b> Projection piece</li><li id="ul0002-0013" num="0071"><b>27</b> Protrusion piece</li><li id="ul0002-0014" num="0072"><b>28</b> Land</li><li id="ul0002-0015" num="0073"><b>30</b> Land portion</li><li id="ul0002-0016" num="0074"><b>32</b> Anchoring portion</li><li id="ul0002-0017" num="0075"><b>40</b>, <b>80</b> Receptacle connector</li><li id="ul0002-0018" num="0076"><b>42</b>, <b>82</b> Housing</li><li id="ul0002-0019" num="0077"><b>43</b> Insertion groove</li><li id="ul0002-0020" num="0078"><b>44</b> Contact</li><li id="ul0002-0021" num="0079"><b>441</b> Contact portion</li><li id="ul0002-0022" num="0080"><b>442</b>, <b>502</b> Fixed portion</li><li id="ul0002-0023" num="0081"><b>443</b>, <b>503</b> Connection portion</li><li id="ul0002-0024" num="0082"><b>444</b>, <b>504</b> Fulcrum portion</li><li id="ul0002-0025" num="0083"><b>445</b>, <b>505</b> Elastic portion</li><li id="ul0002-0026" num="0084"><b>446</b>, <b>506</b> Pressure receiving portion</li><li id="ul0002-0027" num="0085"><b>447</b> Projection</li><li id="ul0002-0028" num="0086"><b>46</b> Locking lever</li><li id="ul0002-0029" num="0087"><b>461</b> Urging portion</li><li id="ul0002-0030" num="0088"><b>462</b> Anchoring aperture</li><li id="ul0002-0031" num="0089"><b>463</b> Shaft</li><li id="ul0002-0032" num="0090"><b>48</b>, <b>88</b> Receptacle shell</li><li id="ul0002-0033" num="0091"><b>50</b> Locking member</li><li id="ul0002-0034" num="0092"><b>501</b> Engaging member</li><li id="ul0002-0035" num="0093"><b>507</b> Extending portion</li><li id="ul0002-0036" num="0094"><b>508</b> Groove</li><li id="ul0002-0037" num="0095"><b>509</b> Flat portion</li><li id="ul0002-0038" num="0096"><b>52</b> Fitting opening</li><li id="ul0002-0039" num="0097"><b>54</b> Fixing tab</li><li id="ul0002-0040" num="0098"><b>56</b> Protrusion</li><li id="ul0002-0041" num="0099"><b>57</b> Elastic piece</li><li id="ul0002-0042" num="0100"><b>58</b> Slit</li><li id="ul0002-0043" num="0101"><b>62</b> Block</li><li id="ul0002-0044" num="0102"><b>64</b> Plug contacts</li><li id="ul0002-0045" num="0103"><b>641</b> Contact portion</li><li id="ul0002-0046" num="0104"><b>643</b> Connection portion</li><li id="ul0002-0047" num="0105"><b>68</b> Plug shell</li><li id="ul0002-0048" num="0106"><b>70</b> Inserting hole</li><li id="ul0002-0049" num="0107"><b>72</b> Fitting portion</li><li id="ul0002-0050" num="0108"><b>74</b> Loading portion</li><li id="ul0002-0051" num="0109"><b>76</b> protrusion</li><li id="ul0002-0052" num="0110"><b>78</b> Anchoring piece</li><li id="ul0002-0053" num="0111"><b>79</b> Contact piece</li><li id="ul0002-0054" num="0112"><b>90</b> Extension portion</li><li id="ul0002-0055" num="0113"><b>92</b> Protrusion</li><li id="ul0002-0056" num="0114"><b>94</b> Flat portion</li></ul>

BEST MODE FOR CARRYING OUT THE INVENTION

0115An electrical connector according to one embodiment of the invention will be explained with reference to the drawings. The electrical connector <b>1</b> comprises a plug connector <b>10</b> and a receptacle connector <b>40</b> which are to be detachably fitted with each other. <figref idref="DRAWINGS">FIG. 1</figref> illustrates in a perspective view the plug connector and the receptacle connector according to the invention fitted with each other. <figref idref="DRAWINGS">FIG. 2</figref> shows in a perspective view the plug connector and the receptacle connector according to the invention prior to the fitting with each other. <figref idref="DRAWINGS">FIG. 3</figref> is a perspective view illustrating the plug connector in <figref idref="DRAWINGS">FIG. 2</figref> being turned upside down. <figref idref="DRAWINGS">FIG. 4A</figref> is a perspective view illustrating the plug connector and contacts and locking members of the receptacle connector according to the invention, and <figref idref="DRAWINGS">FIG. 4B</figref> is a perspective view illustrating the contacts and locking members of the receptacle connector, which are in contact with the plug connector according to the invention. <figref idref="DRAWINGS">FIG. 5</figref> illustrates only the locking lever of the receptacle connector. <figref idref="DRAWINGS">FIG. 6A</figref> illustrates in a perspective view a receptacle connector and a plug connector fitted with each other according to another embodiment of the invention, and <figref idref="DRAWINGS">FIG. 6B</figref> illustrates in a perspective view a receptacle connector and a plug connector fitted with each other according to a further embodiment of the invention. <figref idref="DRAWINGS">FIG. 7A</figref> is a perspective view illustrating a ground bar having protrusion pieces piercing into coaxial cables, and <figref idref="DRAWINGS">FIG. 7B</figref> is a perspective view illustrating the coaxial cables into which the protrusion pieces pierce and whose center conductors are soldered to lands of a flexible printed circuit (FPC) board.

0116The plug connector <b>10</b> of one embodiment of the invention mainly comprises coaxial cables <b>14</b>, a flexible printed circuit board <b>12</b> and a ground bar <b>16</b>. The receptacle connector <b>40</b> of the one embodiment mainly comprises a housing <b>42</b>, contacts <b>44</b>, a locking lever <b>46</b>, locking members <b>50</b> and a receptacle shell <b>48</b>.

0117The components of the respective connectors <b>10</b> and <b>40</b> will be explained hereinbelow. First, the construction of the plug connector <b>10</b> will be explained. With the plug connector <b>10</b>, the coaxial cables <b>14</b> are directly connected to the flexible printed circuit board <b>12</b> and the ground bar <b>16</b> is brought into contact with the braids <b>143</b> of the coaxial cables <b>14</b>, thereby providing a grounding or earthing.

0118The construction of the coaxial cables <b>14</b> will be explained. Each of the coaxial cables <b>14</b> mainly comprises a center conductor <b>141</b>, an insulator <b>142</b>, a braid <b>143</b> as an external conductor, and a sheath <b>144</b>. The center conductor <b>141</b> made of a metal is adapted to be connected to the flexible printed circuit board <b>12</b> and covered by the insulator <b>142</b> thereabout. The insulator <b>142</b> serves to insulate between the center conductor <b>141</b> and the braid <b>143</b> as an external conductor. The insulator <b>142</b> is covered by the braid <b>143</b> as the external conductor. These braids <b>143</b> are connected to the ground bar <b>16</b> to provide the grounding and covered therearound by the sheath <b>144</b> made of an insulating material such as vinyl chloride.

0119Prior to being connected to the flexible printed circuit board <b>12</b>, the coaxial cables <b>14</b> are pre-treated in the following manner. First, the sheath <b>144</b> is removed over a predetermined length and the front portion of the insulator <b>142</b> is then removed to expose the center conductor <b>141</b> of a predetermined length. Finally, the braid <b>143</b> is partly removed to leave the braid <b>143</b> of a predetermined length, while taking care enough to avoid any contact between the center conductor <b>141</b> and the braid <b>143</b>.

0120The flexible printed circuit board <b>12</b> will then be explained. The flexible printed circuit board <b>12</b> is substantially rectangular of 15.1 mm length, 3.05 mm width and 0.12 mm thickness in the illustrated embodiment. The flexible printed circuit board <b>12</b> mainly comprises a required number of lands <b>28</b> each adapted to be connected to the center conductor <b>141</b> and thus adapted to be connected to the contact <b>44</b> of the receptacle connector <b>40</b>, land portions <b>30</b> connected to fixed portions <b>24</b> of the ground bar <b>16</b> and adapted to contact the contacts <b>44</b> at the longitudinally distal ends of the receptacle connector <b>40</b>, respectively and anchoring portions <b>32</b> adapted to engage engaging portions <b>501</b> of the locking members <b>50</b>, respectively. The lands <b>28</b> may be arranged with a pitch corresponding to that of the coaxial cables <b>14</b>. The lands <b>28</b> has a size suitably designed such that they can be connected to the center conductors <b>141</b> (by soldering) with a sufficient connecting strength without giving rise to any defective connection and can contact the contacts <b>44</b> of the receptacle connector <b>40</b> in a stable manner without any failed connection. In the illustrated embodiment, the lands <b>28</b> are of 1.9 mm length and 0.25 mm width with 0.4 mm pitch.

0121The distance between the land portions <b>30</b> may be suitably designed in consideration of the number of the coaxial cables <b>14</b> and the fact that the contacts <b>44</b> at both the ends of the receptacle connector <b>40</b> contact the land portions <b>30</b>, respectively. In the illustrated embodiment, the number of the coaxial cables <b>14</b> is thirty (30) and the distance between the land portions <b>30</b> is 12.4 mm. The contacts <b>44</b> at both the distal ends of the receptacle connector <b>40</b> contact the land portions <b>30</b> and the fixed portions <b>24</b> of the ground bar <b>16</b> are connected to the land portions <b>30</b>. Therefore, the size of the land portions <b>30</b> may be designed such that the fixed portions <b>24</b> of the ground bar <b>16</b> can be connected to the land portions <b>30</b> with a sufficient connection strength and the contacts <b>44</b> at both the distal ends of the receptacle connector <b>40</b> can contact the land portions <b>30</b> in a stable way without giving rise to any failed connection. In the illustrated embodiment, the land portions <b>30</b> are of 3.05 mm length and 1.5 mm width.

0122The anchoring portions <b>32</b> are adapted to engage the engaging portions <b>501</b> of the locking members <b>50</b> so that the shape of the anchoring portions <b>32</b> may be any one permitting the engagement of the anchoring portions <b>32</b> with the engaging portions <b>501</b> of the locking members <b>50</b>. The anchoring portions <b>32</b> may be a U-shaped notch, a through-hole, or a blind hole. In the illustrated embodiment, the anchoring portions <b>32</b> are each an elliptical through-hole as shown in <figref idref="DRAWINGS">FIGS. 2 to 4</figref> in which the two locking members <b>50</b> engage, in order to enhance the holding force when the plug and receptacle connectors are fitted with each other.

0123The ground bar <b>16</b> will then be explained which is a subject feature of the invention. The ground bar <b>16</b> is made by the known press-working from a metal which may be phosphor bronze, beryllium copper, or brass in consideration of workability, dimensional stability, conductivity and ease in plating. The ground bar <b>16</b> comprises a main portion <b>22</b> adapted to contact the braids <b>143</b> of the coaxial cables <b>14</b>, and the fixed portions <b>24</b> at the longitudinal ends contiguous to the main portion <b>22</b> and adapted to be connected to the land portions <b>30</b>. The size of the main portion <b>22</b> depends upon the number of the coaxial cables <b>14</b> and may be suitably designed so as to be able to contact the braids <b>143</b> of all the coaxial cables <b>14</b>. In the illustrated embodiment with the thirty coaxial cables, the ground bar <b>16</b> is of 13.2 mm length and 0.65 mm width. The distance between the fixed portions <b>24</b> at both the ends of the ground bar <b>16</b> is 13 mm in the embodiment which depends upon the number of the coaxial cables. The size of the fixed portions <b>24</b> is 0.5 mm length and 0.4 mm width in the embodiment, which may be suitably designed in consideration of the connection strength to the flexible printed circuit board <b>12</b>.

0124The position at which the ground bar <b>16</b> is fixed to the land portions <b>30</b> may be suitably designed such that the ground bar <b>16</b> is brought into contact with the braids <b>143</b> of the coaxial cables <b>14</b> under the condition that the center conductors <b>141</b> of the coaxial cables <b>14</b> are connected to the lands <b>28</b> of the flexible printed circuit board <b>12</b>.

0125There may be a possibility that no stable grounding is possible by merely bringing the main portion <b>22</b> of the ground bar <b>16</b> into contact with the braids <b>143</b> of the coaxial cables <b>14</b>. Therefore, the main portion <b>22</b> of the ground bar <b>16</b> is provided with projection pieces <b>26</b> protruding from the main portion <b>22</b> at positions corresponding to those between the center conductors of the coaxial cables <b>14</b> with the same pitch as that of the coaxial cables <b>14</b>, or with a pitch equal to every other or every third coaxial cable, or at intervals of plural coaxial cables. According to the illustrated embodiment, in order to ensure a more stable grounding, the projection pieces are provided between all the center conductors and have a substantially L-shape so that the projection pieces securely penetrate between the coaxial cables <b>14</b> when the ground bar <b>16</b> is merely put on the coaxial cables <b>14</b>. The size of the projection pieces <b>26</b> may be suitably designed in consideration of their strength, the pitch of the coaxial cables <b>14</b> and the grounding resulting from the contact with the braids <b>143</b>. In the illustrated embodiment, the projection pieces <b>26</b> are of 0.17 mm width and 0.45 mm length. By providing the projection pieces <b>26</b>, they penetrate between the coaxial cables <b>14</b> so that the projection pieces <b>26</b> and the braids <b>143</b> can be connected without using soldering, thereby precluding any failed connection.

0126In order to fix the ground bar <b>16</b> to the flexible printed circuit board <b>12</b> more rigidly, moreover, projection pieces <b>26</b> are further provided at both the longitudinal ends. Such projection pieces <b>26</b> provided at both the ends of the ground bar <b>16</b> may have a width which is of the order of 0.3 mm larger than that of the normal projection pieces <b>26</b> because the projection pieces <b>26</b> at both the ends are not under the influence of the pitch of the coaxial cables <b>14</b>.

0127In order to prevent the ground bar <b>16</b> from rising away from the coaxial cables <b>14</b>, a required number of the substantially L-shaped projection pieces <b>26</b> extend further beyond the braids <b>143</b> of the coaxial cables <b>14</b> to the opposite side of the flexible printed circuit board <b>12</b> whereupon the extended ends of the pieces are soldered to the opposite side of the board <b>12</b>. The “required number” is here understood as signifying the number enough to prevent the rising of the ground bar <b>16</b>. In the embodiment, every eleventh piece is soldered in the interest of safety.

0128With increasingly higher transmission speed, in order to enhance the shielding, the following approach has been taken according to the invention. The ground bar <b>16</b> is provided with protrusion pieces <b>27</b> contiguously therewith at predetermined positions on the surface of the main portion <b>22</b> of the ground bar <b>16</b> adapted to contact the coaxial cables <b>14</b>. When the ground bar <b>16</b> is put on the coaxial cables <b>14</b>, the protrusion pieces <b>27</b> each pierce into the coaxial cable <b>14</b> so that the protrusion piece <b>27</b> will contact the center conductor <b>141</b> and the braid <b>143</b> of the coaxial cable <b>14</b> as shown in <figref idref="DRAWINGS">FIGS. 7A and 7B</figref>. The size of the protrusion pieces <b>27</b> may be suitably designed in consideration of the diameter of the coaxial cables <b>14</b> and the function described above, strength, and worked accuracy of the protrusion pieces <b>27</b>. In the embodiment with the coaxial cables <b>14</b> of 0.3 mm diameter, the protrusion pieces <b>27</b> extend of the order of 0.20 mm from the main portion. The shape of the protrusion pieces <b>27</b> may be suitably designed in consideration of the piercing power of the pieces in addition to the same factors considered when the size of the protrusion pieces <b>27</b> is determined. In the illustrated embodiment, their shape is tapered toward its tip end in order to easily pierce into the cable. The term “at predetermined positions” is here understood as signifying “at any suitable positions” such as at every other or every third coaxial cable, or at intervals of plural coaxial cables. In the illustrated embodiment, the protrusion pieces are provided at every other coaxial cable <b>14</b> so as to pierce thereinto as shown in <figref idref="DRAWINGS">FIG. 7A</figref>. Also, the protrusion pieces <b>27</b> may be provided at every third coaxial cable depending on the arrangement of signal lines. When the protrusion pieces <b>27</b> each pierce into the coaxial cable <b>14</b> to bring the protrusion piece <b>27</b> into contact with the center conductor <b>141</b> and the braid <b>143</b>, the shielding effect can be enhanced, and further the shielding effect between the lands <b>28</b> of the flexible printed circuit board <b>12</b> can be obtained.

0129The receptacle connector <b>40</b> according to the invention will then be explained. First, its housing <b>42</b> will be explained. The housing <b>42</b> is made by the known injection molding from an insulating plastic material such as polybutylene terephthalate (PBT), polyamide (66PA or 46PA), liquid crystal polymer (LCP) and polycarbonate (PC) and combination thereof, suitably selected in view of the requirements imposed of the housing with respect to dimensional stability, workability, manufacturing cost and the like.

0130The housing <b>42</b> is formed with insertion grooves <b>43</b> into which a required number of contacts <b>44</b> are installed by press-fitting, lancing or hooking, welding or the like. The housing <b>42</b> is also provided with a fitting opening <b>52</b> for inserting the plug connector <b>10</b> (the flexible printed circuit board <b>12</b>). The size of the fitting opening <b>52</b> is suitably designed so that the flexible printed circuit board <b>12</b> can be inserted and the flexible printed circuit board <b>12</b> is urged against the contacts <b>44</b> by means of the locking lever <b>46</b> when the flexible printed circuit board <b>12</b> has been inserted into the housing <b>42</b>. The housing <b>42</b> is provided at its longitudinal ends with bearings for rotatably supporting shafts <b>463</b> of the locking lever <b>46</b>. The shape and size of the bearings may be arbitrarily selected insofar as the shafts <b>463</b> of the locking lever <b>46</b> are rotatable in the bearings and may be suitably designed in consideration of the function of the bearings and the strength and size of the housing <b>42</b>. Moreover, the housing <b>42</b> is provided at longitudinal ends with anchoring portions at positions corresponding to those of locking portions of the locking lever <b>46</b>.

0131The contacts <b>44</b> will then be explained. The contacts <b>44</b> are made by the known press-working from a metal such as brass, beryllium copper, phosphor bronze and the like to fulfil the requirements imposed thereon, springiness, conductivity and the like.

0132The contacts <b>44</b> have a substantially H-shape and each mainly comprise contact portions <b>441</b> adapted to contact the flexible printed circuit board <b>12</b>, a connection portion <b>443</b> to be connected to a board, a fixed portion <b>442</b> to be fixed to the housing <b>42</b>, an elastic portion <b>445</b> and a fulcrum portion <b>444</b> provided between the contact portions <b>441</b> and the connection portion <b>443</b>, a pressure receiving portion <b>446</b> positioned opposed to the connection portion <b>443</b> and extending from the elastic portion <b>445</b>, and further contact portion <b>441</b> extending from the fulcrum portion <b>444</b> and adapted to contact the flexible printed circuit board <b>12</b>. The upper contact portions <b>441</b>, the elastic portion <b>445</b>, the fulcrum portion <b>444</b> and the connection portion <b>443</b> are arranged in the form of a crank. The contact portions <b>441</b> have a protrusion shape to make easy the contact with the flexible printed circuit board <b>12</b>. Although the connection portion <b>443</b> is of a surface mounting type (SMT) as shown in <figref idref="DRAWINGS">FIG. 4</figref>, it will be apparent that it may be of a dip type. In the illustrated embodiment, the two contact portions <b>441</b> are provided to embrace the flexible printed circuit board <b>12</b> therebetween. The two contact portions <b>441</b> are arranged on upper and lower sides of the flexible printed circuit board <b>12</b> so that the board <b>12</b> is embraced by the two contact portions <b>441</b> to ensure the contact between the board <b>12</b> and the contacts <b>44</b>.

0133The fulcrum portion <b>444</b>, the elastic portion <b>445</b> and the pressure receiving portion <b>446</b> function in the following manner when the flexible printed circuit board <b>12</b> is inserted. After the flexible printed circuit board <b>12</b> has been inserted into the fitting opening <b>52</b> of the housing <b>42</b> of the receptacle connector <b>40</b>, when the locking lever <b>46</b> is pivotally moved about its shafts <b>463</b> to pivotally move the urging portions <b>461</b> of the locking lever <b>46</b> in the space between the connection portions <b>443</b> and the pressure receiving portions <b>446</b> of the contacts <b>44</b>, the pressure receiving portions <b>446</b> are urged upwardly by the urging portions <b>461</b> so that the elastic portions <b>445</b> of the contacts <b>44</b> are tilted about the fulcrum portions <b>444</b> toward the contact portion <b>441</b>, thereby urging the contact portions <b>441</b> against the flexible printed circuit board <b>12</b>. The sizes and shapes of the fulcrum portion <b>444</b>, the elastic portion <b>445</b> and the pressure receiving portion <b>446</b> may be suitably designed for achieving such their functions. The pressure receiving portion <b>446</b> of the contact <b>44</b> is preferably provided at its distal end with a projection <b>447</b> which is brought into engagement with an anchoring aperture <b>462</b> of the locking lever <b>46</b> when the urging portions <b>461</b> of the locking lever <b>46</b> are pivotally moved in the space between the pressure receiving portions <b>446</b> and the connection portions <b>443</b> of the contacts. The engagement of the projection <b>447</b> with the anchoring aperture <b>462</b> will prevent the locking lever <b>46</b> from being deformed at its center due to strong reaction against the pivotal movement of the locking lever <b>46</b>. The size of the projection <b>447</b> may be any one insofar as it serves to achieve the purpose described above, and may be suitably designed so as to engage the anchoring aperture <b>462</b> of the locking lever <b>46</b>.

0134While the contacts <b>44</b> are shown in the form of a substantially H-shape, it will be apparent that they may be in the form of a substantially h-shape (not shown) in which there is no contact portion <b>441</b> extending from the fulcrum portion <b>444</b> and adapted to contact the flexible printed circuit board.

0135The locking lever <b>46</b> will then be explained. The locking lever <b>46</b> is made by the known injection molding from an insulating plastic material such as polybutylene terephthalate (PBT), polyamide (66PA or 46PA), liquid crystal polymer (LCP) and polycarbonate (PC) and combination thereof, suitably selected in view of the requirements imposed with respect to dimensional stability, workability, manufacturing cost and the like. The locking lever <b>46</b> mainly comprises shafts <b>463</b> rotatably fitted in the housing <b>42</b>, the urging portions <b>461</b> each adapted to urge the pressure receiving portion <b>446</b> of the contact <b>44</b>, and the anchoring apertures <b>462</b> each adapted to engage the projection <b>447</b> of the contact <b>44</b>. The shafts <b>463</b> are rotatably fitted in both the ends of the housing <b>42</b> so as to be fulcrums for pivotally moving the locking lever <b>46</b>. The locking lever <b>46</b> is further provided at both the ends with locking portions adapted to engage the housing <b>42</b> for preventing the locking lever <b>46</b> from rising away from the contacts when the locking lever <b>46</b> urges the pressure receiving portions <b>446</b> of the contacts <b>44</b>. The shape and size of the locking portions may be arbitrary so long as they can engage the housing <b>42</b> and may be suitably designed in consideration of the function described above and the size and strength of the connector.

0136The urging portions <b>461</b> of the locking lever <b>46</b> are each adapted to be urged against the pressure receiving portion <b>446</b> of the contact <b>44</b> and their shape is preferably elongated and elliptical in the illustrated embodiment. With such an elliptical shape, when the locking lever <b>46</b> is pivotally moved to move the urging portions <b>461</b> in the space between the pressure receiving portions <b>446</b> and the connection portions <b>443</b> of the contacts <b>44</b> so that the pressure receiving portions <b>446</b> of the contacts <b>44</b> are raised with variation in contact height owing to the elliptical shape of the urging portions <b>461</b>, thereby urging the contact portions <b>441</b> of the contacts <b>44</b> against the flexible printed circuit board <b>12</b>. The urging portions <b>461</b> may be any shape insofar as they can be pivotally moved in the space between the pressure receiving portions <b>446</b> and the connection portions <b>443</b> of the contacts <b>44</b> and the pressure receiving portion <b>446</b> of the contacts can be raised with the aid of the variation in size such major and minor axes of an ellipse.

0137As described above, in order to prevent the locking lever <b>46</b> from being outwardly deformed at its middle due to the reaction force against the pivotal movement of the locking lever <b>46</b>, the locking lever <b>46</b> is provided with the anchoring apertures <b>462</b> independently from one another with which the projections <b>447</b> of the contacts <b>44</b> engage, respectively. The placement of the anchoring apertures <b>462</b> independent from one another serves to maintain the strength of the locking lever <b>46</b> and prevent the locking lever <b>46</b> from deforming on being pivotally moves.

0138The locking lever <b>46</b> is mounted on the housing <b>42</b> on the opposite side of its fitting opening <b>52</b> in a pivotally moving manner to achieve potentially the lower geometry in height of the connector.

0139The receptacle shell <b>48</b> will then be explained. The receptacle shell <b>48</b> is made by the known press-working also from a metal such as brass, beryllium copper, phosphor bronze and the like to fulfil the requirements imposed thereon, workability, dimensional stability, conductivity, ease in plating, and the like. The receptacle shell <b>48</b> provides shielding effect to the receptacle connector <b>40</b> and is mounted thereon in a manner covering the housing <b>42</b> except for the locking lever <b>46</b>. The receptacle shell <b>48</b> is provided at both longitudinal ends with fixing tabs <b>54</b> for fixing the receptacle shell <b>48</b> of the receptacle connector <b>40</b> to a hard substrate. The fixing tabs <b>54</b> are fixed to the hard substrate by soldering as by reflow soldering simultaneously with the installation of the contacts <b>44</b> and the locking member <b>50</b>. The fixing tabs <b>54</b> are provided to enable the connected strength of the receptacle connector <b>40</b> to be enhanced. The size of the fixing tabs <b>54</b> may be suitably designed in consideration of the connected strength of the receptacle connector <b>40</b> and occupied area on the hard substrate. The fixing tabs <b>54</b> in the illustrated embodiment are of 0.7 mm×0.35 mm size.

0140Finally, the locking members <b>50</b> will be explained. The locking members <b>50</b> are made by the known press-working from a metal in the similar manner to the contacts <b>44</b>. Preferred metals from which to form the locking members <b>50</b> include brass, beryllium copper, phosphor bronze and the like which fully comply with the imposed requirements such as the springiness, moldability and the like.

0141In the illustrated embodiment, the locking members <b>50</b> have a substantially H-shape similar to that of the contacts <b>44</b> and each mainly comprise engaging portions <b>501</b> adapted to engage the anchoring portions <b>32</b> of the flexible printed circuit board <b>12</b>, connection portion <b>503</b> to be connected to the board, a fixed portion <b>502</b> to be fixed to the housing <b>42</b>, an elastic portion <b>505</b> and a fulcrum portion <b>504</b> provided between the engaging portion <b>501</b> and the connection portion <b>503</b>, a pressure receiving portion <b>506</b> extending from the elastic portion <b>505</b>, and extending portions <b>507</b> from the fulcrum portion <b>504</b> in the direction opposite to the connection portion <b>503</b>. The engaging portions <b>501</b>, the elastic portion <b>505</b>, the fulcrum portion <b>504</b>, and the connection portion <b>503</b> are arranged substantially in the form of a crank. Moreover, the locking member <b>50</b> is provided with grooves <b>508</b> at positions corresponding to the engaging portions <b>501</b> when they engage the anchoring portion <b>32</b> of the flexible printed circuit board <b>12</b>. The shape and size of the grooves <b>508</b> may be suitably designed in consideration of the strength of the locking member <b>50</b> and so as to achieve the engaging relation between the flat portions <b>509</b> of the engaging portions <b>501</b> and the anchoring portion <b>32</b> when the engaging portions <b>501</b> of the locking member <b>50</b> engage the anchoring portion <b>32</b> of the flexible printed circuit board <b>12</b>. The radius of the rounded distal ends of the engaging portions <b>501</b> may be suitably designed in consideration of the strength and so as to achieve the engaging relation described above. In the illustrated embodiment, the groove <b>508</b> is of 0.08 mm depth and is a curved recess, and the radius of the rounded distal ends of the engaging portion <b>501</b> is 0.05 mm. The connection portion <b>503</b> in the illustrated embodiment is shown of a surface mounting type (SMT), but it may be of a dip type.

0142The elastic portion <b>505</b>, the fulcrum portion <b>504</b>, the pressure receiving portion <b>506</b>, and connection portion <b>503</b> have the same functions and effects as those in the contacts <b>44</b>.

0143The engaging portions <b>501</b> of the locking member <b>50</b> are provided at positions corresponding to the anchoring portion <b>32</b> of the flexible printed circuit board <b>12</b>. The locking members <b>50</b> are each fixed to the housing <b>42</b> by press-fitting, lancing or hooking or the like such that the connection portion <b>503</b> of the locking member <b>50</b> is located on the opposite side of the fitting opening <b>52</b> of the housing <b>42</b>, thereby enabling the engaging portions <b>501</b> to engage the anchoring portion <b>32</b>. The size of the engaging portions <b>501</b> may be suitably designed to obtain required holding force sufficiently, and the shape of the engaging portions <b>501</b> may be any one insofar as they can engage the anchoring portion <b>32</b> of the flexible printed circuit board <b>12</b>. In the illustrated embodiment, the engaging portion is substantially in the form of a right angled triangle in consideration of the holding force so that its vertical surface is caused to contact the surface of the anchoring portion <b>32</b> of the flexible printed circuit board <b>12</b>. Namely, the groove <b>508</b> is provided so that the flat portions <b>509</b> of the engaging portion <b>501</b> engage the anchoring portion <b>32</b> when the engaging portions <b>501</b> of the locking member <b>50</b> engage the anchoring portion <b>32</b> of the flexible printed circuit board <b>12</b>, thereby ensuring the engagement of the locking member <b>50</b> with the flexible printed circuit board <b>12</b> without disengagement of the locking member <b>50</b>. In the illustrated embodiment, as shown in <figref idref="DRAWINGS">FIGS. 4A and 4B</figref>, there are provided two locking members <b>50</b> at each end, that is, there are totally four locking members <b>50</b> in order to more increase the holding force when the plug and receptacle connectors <b>10</b> and <b>40</b> are fitted with each other.

0144In the illustrated embodiment, the engaging portions <b>501</b> do not engage the anchoring portion <b>32</b> when the flexible printed circuit board <b>12</b> is inserted into the fitting opening <b>52</b> of the housing <b>42</b>, but the engaging portions <b>501</b> will engage the anchoring portion <b>32</b> when the flexible printed circuit board <b>12</b> is urged against the contacts <b>44</b> by means of the locking lever <b>46</b>.

0145Another receptacle connector <b>40</b> according to the invention will be explained with reference to <figref idref="DRAWINGS">FIGS. 6A and 6B</figref>. The receptacle connector <b>40</b> now explained comprises a housing <b>42</b>, contacts <b>44</b>, and locking members <b>50</b> which are substantially similar to those described above. A receptacle shell <b>48</b> only will be explained which is different from the receptacle shell described above. Forming the subject feature of this receptacle connector <b>40</b> is at least one contact means provided at a fitting opening <b>52</b> of the receptacle shell <b>48</b> and adapted to contact the upper surface of a ground bar <b>16</b> of a plug connector <b>10</b>. With the contact means, the receptacle shell <b>48</b> and the ground bar <b>16</b> are securely caused to contact each other to ensure the continuity across the plug and receptacle connectors <b>10</b> and <b>40</b> and hence across coaxial cables <b>14</b> and a hard substrate, thereby providing grounding.

0146The contact means can be realized in the following manner. There are provided in the fitting opening <b>52</b> protrusions <b>56</b> extending into the fitting opening <b>52</b> as the contact means. Only one protrusion <b>56</b> may be enough to be sure to contact the ground bar <b>16</b> of the plug connector <b>10</b>. In the illustrated embodiment, three protrusions <b>56</b> are provided in consideration of stability of contact and balancing when being fitted. The extending distance of the protrusion <b>56</b> may be suitably designed in consideration of fitting of the plug and receptacle connectors <b>10</b> and <b>40</b> and contact pressure and fitting (fitting power) between the receptacle shell <b>48</b> and the ground bar <b>16</b>. As a result, the protrusions <b>56</b> preferably extend of the order of 0.18 mm. It is unfavorable to cause the protrusion <b>56</b> to extend 0.18 mm at a time in forming step, as considering the workability and strength of the receptacle shell <b>48</b>. In the illustrated embodiment, therefore, as shown in <figref idref="DRAWINGS">FIG. 6A</figref> the protrusions <b>56</b> are caused to extend 0.1 mm in a rectangular shape and further to extend 0.08 mm in a circular shape. The shape of the protrusions <b>56</b> may be arbitrary insofar as the receptacle shell <b>48</b> and the ground bar <b>16</b> can contact each other, such as hemispherical, triangular pyramidal and simply extending shape. In the illustrated embodiment, the hemispherical protrusions are used in consideration of stability of contact and balancing when being fitted.

0147As another contact means for the receptacle shell <b>48</b>, an elastic piece <b>57</b> may be used which extends into the fitting opening <b>52</b> and has an elasticity. The elastic piece <b>57</b> may be formed by forming slits <b>58</b> on both sides of the piece <b>57</b>. Moreover, the elastic piece <b>57</b> may be curved convex as the anchoring pieces <b>78</b> and contact pieces <b>79</b> of the prior art plug connector <b>60</b> shown in <figref idref="DRAWINGS">FIGS. 8 and 9</figref> illustrating the prior art. Only one elastic piece <b>57</b> may be enough to be sure to contact the ground bar <b>16</b> of the plug connector <b>10</b>, but the number may be suitably determined in consideration of stability of contact, contact pressure and balancing when being fitted. The extending distance of the elastic piece <b>57</b> may be suitably designed in consideration of the fitting of the plug and receptacle connectors <b>10</b> and <b>40</b>, contact pressure between the receptacle shell <b>48</b> and the ground bar <b>16</b>, and strength and fitting (fitting power) of the elastic piece <b>57</b>. As a result, the elastic piece <b>57</b> preferably extends of the order of 0.18 mm. The shape of the elastic piece <b>57</b> may be arbitrary insofar as the receptacle shell <b>48</b> and the ground bar <b>16</b> can contact each other. One example of the shape is curved convex.

0148A further contact means is a combination of the protrusion <b>56</b> and the elastic piece <b>57</b> as shown in <figref idref="DRAWINGS">FIG. 6B</figref>. In suitably designing the contact means in consideration of the fitting of the plug and receptacle connectors <b>10</b> and <b>40</b>, contact pressure between the receptacle shell <b>48</b> and the ground bar <b>16</b>, and strength and fitting (fitting power) of the elastic piece <b>57</b> as in the above case, the contact means have been found preferable to extend of the order of 0.18 mm and such a combination is employed in the embodiment. First, the receptacle shell <b>48</b> is formed substantially at the middle with two slits <b>58</b> to form an elastic piece <b>57</b> and then the elastic piece <b>57</b> is provided at both ends with two protrusions <b>56</b>. In the illustrated embodiment, the elastic piece <b>57</b> extends 0.1 mm and the protrusions <b>56</b> extend 0.08 mm. The size of the elastic piece <b>57</b> may be suitably designed in consideration of the stability of contact, contact pressure, balancing when being fitted and fitting (fitting power). In the illustrated embodiment, the elastic piece is of 3 mm length.

0149Examples of application of the invention are plug connectors for use with mobile phone or cellular telephone, note book personal computer, digital camera and the like. Particularly, the invention achieves the low geometry in height of the plug connector and hence the receptacle connector, which is very beneficial for these appliances.

0150The connector of one preferred embodiment of the invention comprises erroneous insertion preventing means for preventing the plug connector turned upside down from its correct position from being inserted into the receptacle connector. <figref idref="DRAWINGS">FIGS. 10 and 11</figref> illustrate the plug and receptacle connectors immediately before and after being fitted with each other in their correct positions, respectively. <figref idref="DRAWINGS">FIG. 12</figref> illustrates the erroneously inserted plug connector into the receptacle connector being prevented from further insertion by means of the erroneous insertion preventing means and <figref idref="DRAWINGS">FIG. 13</figref> shows the preventing means viewed from opposite side of the connectors.

0151As shown in <figref idref="DRAWINGS">FIGS. 10 and 13</figref>, the ground bar <b>16</b> of the plug connector <b>10</b> is provided with protrusions <b>92</b> at both the ends. In the illustrated embodiment, the fixed portions <b>24</b> of the ground bar <b>16</b> are somewhat extended in the insertion direction of the plug connector <b>10</b> to form extension portions <b>90</b>, each of which is further provided with the protrusion <b>92</b> substantially perpendicular to the extension portion <b>90</b>. If the plug connector <b>10</b> erroneously turned upside down and is being inserted into the receptacle connector <b>40</b>, the protrusions <b>92</b> abut against flat portion <b>94</b> of the housing <b>42</b> of the receptacle connector <b>40</b> so that further insertion of the plug connector is prevented. In this state, the flexible printed circuit board is not in contact with contact portions of the contacts of the receptacle connector so that no damage to contacts and circuit board occurs. When an operator finds out the erroneous insertion by the abutment of the protrusions <b>92</b> of the ground bar <b>16</b> against the housing <b>42</b>, the plug connector can be easily pulled out or retracted from the receptacle connector, and the plug connector in correct position can be inserted into and connected with the receptacle connector without any failed connection. The projections <b>92</b> and the flat portions <b>94</b> may be formed in any shape and size so long as they achieve the above functions as erroneous insertion preventing means.